The present invention relates to an operation changeover mechanism, in an apparatus having three members relatively movable in the same direction to each other, for selectively performing relative movement between a predetermined one of the three members and each of the other two.
For example, Japanese Laid-Open Patent Application No. 53872/1982 discloses an example of such an operation changeover mechanism provided in a bookshelf-type record player. This operation changeover mechanism, as illustrated in FIG. 1A, selectively and alternatively causes either one of a slide base 201 and a rack 205, both being mounted in a player cabinet and movable in the forward/backward direction, to move relative to the player cabinet so as to cause the slide base 201 and a tone arm TA to operate independently from each other. In brief, this operation changeover mechanism is constituted by recess portions 304 and 305 respectively formed in opposite portions in the slide base 201 and the rack 205, a lock lever 307 on which lock pins 307a and 307b engageable with the respective recess portions are projectingly provided at a swing end portion, and a drive mechanism for selectively swing driving the lock lever.
Another example of the operation changeover mechanism which is incorporated into a front loading disk player is proposed in Japanese Utility Model Application No. 152505/1983 filed by the present applicant. As shown in FIG. 1B, this front loading disk player includes a tray 423 attached to a horizontal chassis 418 movable in the forward/backward direction, a container 427 mounted on the tray and movable in the upward/downward direction, a cam member 435 having a cam hole engaged with the container 427 and mounted on the tray 423 and movable in the forward/backward direction, and a drive force applying device for applying a drive force in the forward/backward direction to the cam member. The operation changeover mechanism operates to selectively effect relative movement between the tray 423 and either one of the horizontal chassis 418 and the cam member 435 so as to move the tray 423 relative to the horizontal chassis 418 and move the container 427 relative to the tray 423 from each other. This operation changeover mechanism includes a device having a cam plate 475, an inhibit plate 478 for locking the container 427 to the tray 423 until the tray 423 has been received within a player housing, and an inhibit mechanism, including an inhibit member 483, an inhibit shaft 486, and, an inhibit lever 485, for inhibiting the movement of the tray 423 relative to the horizontal chassis 418 when the tray 423 has been received within the player housing.
In the first example of the operation changeover mechanism as described above, the total number of parts, such as the lock lever 307, the lock lever drive mechanism, etc., is large and therefore the cost is high. Also in the second example of the operation changeover mechanism as described above, the number of parts is large and the cost is therefore high. Further, the operational timing of the lock mechanism and the inhibit mechanism must be precisely controlled, and therefore it is necessary to manufacture the respective members with a high accuracy. In addition, it is difficult to assemble the various members.
The record player devices to which the invention pertains are adapted to receive an optical information recording disk such as a video disk or a digital audio disk either of which has on its surface fine pits in the form of a spiral track in a pattern, in accordance with an information signal, that records the information signal. In order to read out the recorded information signal, a light spot is irradiated on the track while the disk is rotated at a predetermined speed. Changes in the reflected light are converted into an electric signal to thereby reproduce the original information signal. In order to cause the irradiation spot to be focused exactly on the track and to follow the track, it is necessary to prevent external vibration from influencing a spindle motor carrying a turntable and an optical pickup for performing the spot irradiation. A conventional optical information disk player that uses this technology is shown in FIG. 2.
In FIG. 2, a chassis 501 is affixed in a housing (not shown) of a player. A subchassis 503 is suspended by float springs 502 acting as vibration absorbing members on the under surface of the chassis 501. On the subchassis 503 there is affixed a spindle motor 506 carrying a turntable 505 on which a disk 504 is mounted, and there is further provided a carriage carrying a optical pickup (not shown) that is movable in the radial direction of the disk. On the chassis 501 there is projectingly provided a bracket portion 509 on which a movable member 511 is swingably provided through a connecting member 510. Though not shown in the drawing, the connecting member 510 is arranged to be adjustable in the direction of its length. At a swing end portion of the movable member 511 there is rotatably supported a pressing member 512 for clamping the disk in cooperation with the turntable 505. The pressing member 512 is of the type which is attracted to the turntable 505 by magnetic force.
As described above, in the conventional optical information recording disk player, the carriage 507 carrying the pickup and the spindle motor 506 is fixed on the subchassis 503 which is held by the chassis 501 through the float springs 502, and a clamp mechanism is provided on the chassis 501 fixed to the housing. That is, the spindle motor 506 (and hence the turntable 505) and the clamp mechanism are relatively movable within the range of movement of the float springs 502 in the play mode of the disk. Accordingly, it has been necessary to make considerably large the dimension Ga indicated in FIG. 2, that is, a gap formed at the pressing member 512, in order to release the abutting condition between the movable member 511 and the pressing member 512 to enable the pressing member to rotate together with turntable 505 in the play mode of the disk. This problem should be solved to make the player thin overall.
To ensure the dimensional accuracy in relative position between the turntable 505 and the pressing member 512, it has been necessary to increase the accuracy of the position of the spindle motor 506 relative to the subchassis 503 and the positions of the subchassis 503 and the clamp mechanism relative to the chassis 501 and the dimensional accuracies of these components, resulting in a high cost. Further, for example, in order to obviate the necessity of exact positioning of the clamp mechanism on the chassis 501, it has been necessary to provide an extra part such as the connecting member 510 as a position adjusting device, as shown in FIG. 2.